Home Next Meeting Location Previous Meetings Membership Rules Links Contact Yahoo! Groups Members
General Meeting Reports for 1998 Return to Index
October 1998 The Lowther Club of Australia and NZ

There's nothing quite like talking to a true enthusiast, and the guys from The Lowther Club of Australia and New Zealand who presented the program at our last General Meeting illustrated the point once again.

Mohan Varkey and a group from the club were demonstrating a new model Lowther speaker called the Academy. The name Lowther has been around almost as long as any name in audio, 50 years at least, and the current owners of the name are fanatical about remaining true to the original concept. This means not only sticking to the idea of a single, full-range driver in a horn-loaded enclosure of modest dimensions, but even going so far as to retain almost unchanged the original Lowther driver designs.

Now Lowther is not a name on every high-end audiophile's lips in 1998. More like a cult brand. But it must have some pretty potent virtues (a) to still exist in almost unchanged form for so long, and (b) to lead perfectly sane men (women too, for all I know) to worship the name with a fervour usually reserved for a religion or a woman. So what is the average audiophile to make of this. Is it the ultimate "golden oldie" or just a hopeless dinosaur? Consider the features.

High sensitivity, you say? Mohan said during the meeting that he has not seen a measurement of the sensitivity of the Academy design, but that an earlier design employing just one Lowther driver measured at 100 dB per watt per metre. In today's terms, that's a very sensitive system. At any reasonable listening levels, then, only very small voice-coil excursions are called for, so one source of possible speaker distortion is minimised. Good, good. Furthermore, despite all the talk from the conservative "measurements" people, plenty of audiophiles have found that there are some low power amplifiers which can sound very beguiling indeed. For these people, high sensitivity allied with speed and accuracy would appear to offer the ideal speakers. Mohan said that he can produce sound pressure levels of 105 dB with a simple 3 watt amp playing an LP EMI OASD 3117 (Carl Orff: Carmina Burana; London Symphony Orchestra/Andre Previn). No clipping was evident on an oscilloscope attached to the secondary of the output transformer.

Only, well what do we really think about horn loading? It imposes pretty complex constructional problems, and I guess that means expense. Let's assume we can handle all that. The next problem is size. My understanding of the Physics of the horn is that you simply cannot do horn loading properly in a commercial speaker. You either do without low frequencies, or the thing is so large that you need to abandon the house and live in the speaker.

Full-range drivers, eh? I think there are a few other speaker systems around which use them. Hen's teeth are more common though. Many of us know from experience how crucial it is to the performance of a speaker system to have really well designed and built crossover filters. Lowther is surely right, however, when they say there is no crossover design anywhere as good as no crossover.

On the other hand. We've got to face it sooner or later. There is serious doubt isn't there whether a single driver can deliver good, uncoloured sound across all audible frequencies? And when the religious rules of the brand say that the drivers must stay essentially the same as they were in some far off past, there just could be something of a problem here.

Mohan has no doubts. To him, anyone who likes electrostatic speakers will like Lowthers. By that he means that they are fast, coherent and open-sounding. The Academy system on display contains two full-range Lowther PM7C/Hi-Ferric drivers, 190 mm diameter. The driver has one voice coil but dual concentric paper cones. The ceramic magnet gives flux density of 19,800 gauss. The two drivers are wired in series, so the system is nominally a 16 ohm one. The enclosures, made for Mohan by a local cabinet maker, use high quality plywood, and the display models were beautifully made and finished. The truncated horn fits into a rectangular enclosure which is 100 cm high x 29 cm wide x 43 cm deep, and they weigh about 60 kg each. The two drivers are mounted with separate throat areas and expansion chambers within the cabinet, leading into a common horn space. One driver points forward, the other (mounted without the usual phase plug, points upwards and is angled towards the rear. The four drivers in the pair of Academy speakers will cost you about $3000, and the plans for the cabinet can be obtained by joining the Lowther Club. You can build them yourself (it will require some well refined carpentry skills) or have them built for you, perhaps at a cost around $1500 the pair.

To demonstrate the speakers to the club, Mohan used a Cambridge Audio CD3 CD player, a Scott Type 130 valve pre amp, and a pair of Quad II valve mono power amps. Mohan produced a printed hand-out listing his music program, some 12 items. The first two items came from a CD titled ANUNA, on the Danu label, female vocals with a choir and instrumental backing. It was recorded in a highly reverberant acoustic. Next was part of Vaughan Williams' English Folk Song Suite played by Arthur Fiedler and the Boston Pops on Decca. All of the music up to here sounded to me as though it was coming at me down a long concrete tunnel, and my heart was starting to sink. Was this what Lowthers sounded like? In the event, it was just the way those first items had been recorded, for the very next item was a real knock-out! A number from the old D'Oyly Carte recording on Decca of Pirates of Penzance. Clear, forward and very detailed male lead voice, and the male chorus was spacious and, wow!

And so it went. Some of the items I found a touch disappointing – cymbals like crumpled paper rather than ringing metal, guitar sounding distant or lacking in "presence", and once or twice a loss of clarity as, say, a choir started to build up the sound level. At other times, I found a nice effortlessness about the sound. Vocals were usually very convincing. Two of the tracks played stand out in my memory as real gems. They were the Gilbert and Sullivan excerpt mentioned above, and one on the Impulse label, a CD entitled Love Scenes featuring Diana Krall. The reproduction of the voice was just superb, and the very dynamic backing was done to great effect.

After supper, our music convenors (except Bill L, who had to leave early) presented a couple of numbers each. My reaction to the speakers was up and down. Sometimes I was uplifted by the "togetherness" of the sound, or its effortless wallop. There was great spaciousness often, and it was usually possible to form a good impression of where the performers would have been in space. At other times my enthusiasm was lowered by a sort of honkiness, like music coming from another room down a corridor.. Sometimes the lack of real deep bass was apparent, and I sometimes felt a lack of sparkle, like a dropping away of high treble response.

It had been a thoroughly enjoyable evening. The enthusiasm of the presenters was fabulous, the musical demos well chosen to give us great variety, and the whole thing very well don indeed. As to being converted to the religion of Lowtherism - I think I can see what the adherents see in them, but I couldn't quite get around to being converted. Those who would like to get into Lowther may contact Mohan by phone on 041 900 9115 or leave a message on 0500 566 616.

September 1998 NOT JUST FOOTBALL PREMIERS

They don't only win football premierships in Adelaide. But just a couple of weeks before the Crow invasion that ended up in the slaughter of the Roos, Garth Pennington took the same journey from Adelaide to Melbourne to show off his Lorpen HP3 speakers.

Before referring to the speakers on display for the night, Garth gave us a highly entertaining sketch of his background in audio. Originally a Telstra technical officer who had long held an interest in music and hi-fi, Garth came to know a group of other like-minded enthusiasts in Adelaide. Over the years they each tried building "enthusiasts" speakers for themselves. One guy tried a concrete bass enclosure build from glued-together concrete garden slabs. Another effort involved home made ribbon panels. There were three elements covering different parts of the frequency spectrum, with rows and rows of little magnets. Poor dispersion was a problem, but in the right spot, they were detailed and fast and sweet. Somebody called Wayne got into horn speakers, and conceived the idea of building folded corner horns , floor to ceiling, cast in concrete. Each horn was cast in 8 segments. Fitted with Audax drivers, they went down below 30 Hz at about 110 dB per Watt per metre sensitivity.

While he watched others in the group doing their things, Garth developed an interest in open baffle planar speakers. They seemed to perform with speed and accuracy, but if reasonable bass extension is required, they have to be so large that most people give up - the baffle must be at least something like 2 metres high by 750 mm wide. Garth fiddled and tried all sorts of variants. He got to trying various sorts of vertical arrays of drivers (two rows of 6 each, single row of 8 etc) on open baffles, and in time was able to use computer techniques to predict quickly the various wave interactions resulting from various driver layouts. He devised many systems that gave very satisfying results, and then turned to trying a commercial viable version. How small could one of these arrays be without unduly compromising the performance? In the end, he has solved the problem of the large open baffle by leaving the lowest frequencies to a separate boxed enclosure for a bass driver. This might solve one problem, but immediately opens up another one – how to match the sonic characteristics of the box bass and the open baffle mid/treble.

In the current version being demonstrated at the meeting, the Lorpen HP3, Garth has a 40 litre ported bass enclosure, fitted with a 210 mm Vifa driver. On the open baffle rising up to 1200 mm from the floor, there is one Focal TC90DX 30 mm dome tweeter with four Alltronics (?) C 3055 mid range drivers spaced equally above and below the tweeter. The open panel is a massive structure, made from 2 pieces of 25 mm custom board glued together. Cross over frequencies are about 250Hz and 3200 Hz, and the whole thing weighs about 30.5 kg. Garth reckons they have a sensitivity of 90.5 dB per watt per metre on axis, and the impedances run between 5 and 16 ohms. They sell for just under $3000 a pair.

The enclosures were beautifully made and finished, almost completed shrouded in black cloth (including around the back, where the drivers produce interesting looking lumps!). Attractive polished wood strips down the edges of the open baffle serve to clamp the cloth covers firmly.

To let us hear them, Garth hooked up a Sony CDP X7ESD CD transport with a Music Labs DP 102 DA converter, a custom made pre-amp, and a pair of VTL "Compact 100" monoblock power amps. A variety of music was heard. We started with Merril Bainbridge on a CD entitled The Garden, then heard "Nerada Nutcracker", an arrangement of some of Tchaikovsky's ballet for a small orchestral group. Next was some rock from a group called Focus, on a CD entitled Moving Waves, some Celtic music on Celtic harps with string backing, a little from Carl Orff's Carmina Burana on a Telarc CD, and Nimrod from Elgar's Enigma Variations. I was impressed by the clarity and sweet, open sound, especially in the midrange and treble areas. The open baffle certainly does have its attractions. In every track, the music came through crisp and clean. I found the bass performance to be adequate, but not outstanding. Several times as I listened, the thought came to me that if the bass performance could be upgraded to the same sort of openness that was being heard higher up, we would have a superb speaker.

The HP 3s are designed as floor-standing models, with no stands. However, I had warned Garth that the hollow-box platform at the front of the Willis Room could compromise bass performance if he placed his speakers on the dais. With this in mind, yet wanting to get some treble to fire over the front row in the audience, Garth had placed his speakers on a couple of low tables that happened to be in the room. Whilst these were quite solid as coffee tables go, they were never built to speaker stand specifications. After we had done a fair bit of listening, Garth tried taking the speakers off the coffee tables, and setting them firmly on the concrete floor in front of the dais. What a pity we had not tried this earlier! The bass became both cleaner and stronger, and there was a general overall sonic improvement.

One interesting observation that I made on several occasions through the night, and I moved to two or three spots in the room to check whether it was specific to certain spots in the room, was that there was often very uncertain imaging. Sometimes it sounded almost as if there was a stereo/mono switch on an amp inadvertently turned to mono. To what extent this was a function of (a) the radiating patterns of flat, open-baffle panels, or (b) the room, or (c) what I had eaten for dinner that evening, I am unable to say. Other audience members agreed that they could pick up the same effect at times.

My overall assessment was that, when placed where intended, on a solid floor, they gave clean, clear sound, with heaps of punch. The midrange and treble portions of the spectrum were especially attractive, but an intending purchaser might be well advised to arrange a home demonstration before plunging. Just to check on imaging and stereo effects in the particular room. The meeting was highly entertaining, and all present would have enjoyed it greatly. We understand that Garth is hoping to organise a retail outlet in Melbourne shortly, but in the meantime we can make our enquiries directly on 618 8341 8201.

August 1998 YAMAHA SURROUND SOUND DONE PROPER

Yamaha presented yet another Home Theatre demonstration at our August General Meeting on August 12th, the first I have heard which convinced me that Home Theatre could be good for straight music reproduction. When we walked in to the Willis Room just before 8pm, we found a Home Theatre set up many would kill for. The room was set up like this.
 
 

SCREEN
NS10MT 
FRONT EFFECTS 
(L)
NS10MT 
FRONT EFFECTS 
(R)
NS1000 
MAIN(L)
NS100 
CENTRE
NS1000 
MAIN(R)
YST.SW.300 
SUB WOOFER
.
PROJECTOR
.
.
NS10MT
REAR EFFECTS 
(L)
 YST.SW.300
SUB 
WOOFER
 NS10MT 
REAR EFFECTS 
(R)

 
 
 
President Peter introduced Wally Bouw. That well known MAC personality from years ago, the old Speaker Bender himself, is now with Yamaha. After a short introduction into the Yamaha philosophy, Wally introduced Phil Hawkins and the rest of his team, who presented the night's program.

"Who would like a pair of Yamaha NS1000"s for $699?", asked Phil. At least that's what I thought he said. He had my full attention, even though he corrected me later, stating that if the NS1000 was still in production, it's price wouild be nearer $10,000 a pair. "You can't get the Berylium for the domes, you know".

Yamaha has been researching surround sound for two decades, making detailed studies of the acoustic available from a large number of venues. I think it was Barry Hann who had one of their earlier surround sound synthesisers, the $1500 DSP 1, more than ten years ago. With this unit you could dial up synthesised impressions the acoustic pattern of all sorts of auditoriums from very large Cathedrals, with l-o-o-o-o-o-n-g reverberation times, through well known European Concert Halls, to an intimate Jazz Club.

Now especially with film soundtracks, and with a small number of dedicated music records, attempts are being made to record the sound track with a microphone placement which will produce a genuine ambience component with a standard speaker layout in an attempt to simulate the acoustic flavour of the venue we are supposed to be in.

Whereas early attempts at multi channel sound had to be condense the multi channel information on to a 2 channel sound carrier, we now have several competing coding systems, using more or less transparent compression algorithms which are capable of storing several discrete audio channels, along with the visual information, on to developments from conventional CD technology, supplementing the large Videotape market.

Of the two major competing systems currently available, Yamaha feels that the DTS system is the better system technically, giving slightly better imaging and Dynamics, Dolby Digital is more user friendly, and is possibly the front runner in the battle to be accepted as the Video and Cable didstribution standard. At this time Yamaha is concentrating on the Dolby Digital system, while keeping a close watch on developments on the DTS front.

At present Yamaha employs 7 channel processing, and is working towards 9 channel processing.

So to the demonstrations:-

We started with a clip from Jurassic Park 2, where several poor humans were trapped inside a large Van, set out as a scientific field unit. Heavy foot stamping, and I mean H-E-A-V-Y from the nasty Tyrannasaurus Rex shook the van and the assembled scientists, (we know they were scientists because some of them were wearing white coats) When after some dramatic roaring and stomping around, T-REX pushed the van over the cliff, and it was held suspended by a fortunately placed octopus strap, one of the occupants, the heroine of course, and a large number of heavy tools, fell onto to the rear glass door, which was obviously not safety glass since it proceeded to crack, with truly alarming crashes and thuds, and we expected to see the lady deposited screaming at the base of the cliff, so that the noise would seem like the Dinner Gong to the rampaging T-REX. Fortunately the hero, thanks to a clever piece of editing, was able to extend his arm the requisite 30 cm. and take the Lady home from T-Rex"s dinner party. I am sorry if I sound flippant, but I do wonder at the use of such marvellous technology to support such a fatuous story. The sound effects were really well done, sounding true to life(?), and extremely dynamic. This prompted the comment that a dynamic range that was fine in a demonstration, would prove to be totally unacceptable in the family lounge room near the kid's bedrooms, and the question; Can you reduce the dynamic range? The answer was that some reduction was possible in the set up menu.

The next demonstration was a sound only demonstration of "Havanna Nights" from the Bottom Line Jazz Club in New York. I thought this was very good indeed, with a generally firm and deep image set between the front speakers. Minor quibbles were that the bass was somewhat boomy, and at one stage I heard percussion coming from the right rear effects speaker. But then I was probably too close to the rear right corner for a balanced sound field.

For me the highlight of the night was the Ivan Butekoff choral arrangement of Tchaikowsky's 1812 Overture. This was superb choral sound, rich, full, and tonally correct; with the choir set in a large reverberant sound field; but again with some extraneous sound from the rear right speaker when the full orchestra entered.

At this stage it was noticed that the Soundfield Synthesiser was set to "Large Cathedral" . The setting was changed to "European Concert Hall" and the item repeated. The fine sound remained while the niggling quibbles dissappeared.

Following yet another inconclusive discussion on the Zoning of source material and players for home use in this region, and a rather inconclusive and I must say unconvincing defense of the practice, we saw another film excerpt, this time from the Movie "In The Line Of Fire" starring Clint Eastwood. This was a most convincing demonstration of the capabilities of home theatre, with a fine rendition ( I use the word advisedly) of spectacular sound effects.

To summarise, this was as good a system as I have been able to see and hear. More to my interest, not being a dedicated movie buff, the musical items showed that good sound need not be a mere accessory to dreadful movies. The system we saw tonight showed that properly managed multichannel sound did place the listener in the middle of a realistic soundfield. If this research which is driven by the requirements of Home Theatre, does produce an improved dedicated music storage system, we will all be advantaged. The listener is taken from the window looking into the auditorium, and placed in a realistic soundfield, a vast improvement. It was obvious that this will enhance our enjoyment of our home music systems.

Phil did apologise for the quality of the video projector. While it did not have the definition of one other we have seen, (which cost more than $20000) I thought it was more than adequate. However, I have to say that I thought Yamaha's system was developed to optimise the audio quality, possibly at the expense of the vision. Other systems we have seen recently maximised vision quality, but at the expense of the best possible audio.

Thanks to Yamaha, Wally Bouw, Phil Hawkins and his team, for a very convincing demonstration.

May 1998 Audio Trends present Home Theatre -Where It's At

The people at Audio Trends in Wantirna, have certainly embraced the current push towards Home Theatre and surround sound, and their demonstration of the state-of-the-art in these areas given to our May General Meeting was as professional a demonstration as you could ever hope to see.

MAC members arrived at the Willis Room to find the place already packed - Audio Trends had advertised the meeting and invited interested members of the public to come as guests. In the end, well over 100 people attended.

The program started with an informal question and answer segment to explain the basics of DVD and DSP. The Digital Video Disc is a 5 inch data storage disc with the capacity to store a great deal more data than we are accustomed to with Compact Discs. Originally conceived as a video carrier to replace the video-cassette, these discs can also hold audio data or computer data, etc. Several rival formats have been developed for laying down video and audio data on to DVDs. AC3 (now called Dolby Digital) was an early leader in the filed, but now there is a strong trend towards a later system called DTS. "Digital Theatre Systems", like Dolby Digital, is a 5.1 system, meaning that there are 5 discrete full-range audio channels plus a single sub-woofer channel, and this has set out to become accepted as the industry standard for both audio and video.

The visual side of the demonstrations was produced using a Davis Powerbeam 5 projector (worth about $13,000) coupled to a Pro-Vision Line Doubler ($6,000). These had been provided by Eastern Audio Visual Systems of Lilydale, who explained that for those who wish to project their video images to a full screen size, there are now three basic types of projector. The older LCD projectors are still available ($8,000 upwards for a good one), which are single-turret straightforward, easily handled units. Much trickier to set up, requiring careful alignment, and not an option if you want to move them about from place to place, are the three-lens CRT projectors. The Davis projector used in the demo was a new type of single lens projector called DLP ("Digital Light Processing"). These use a complex micro-chip which bears 508,000 tiny hinged mirrors. The projectors need no complex setting up, and do not show individual pixels of light on the screen like the older LCDs. Picture quality is enhanced by the use of a line doubler, which increases the scanning rate as the signal is being fed into the projector.

The discs used in the demonstration were played on a Sony S700 DVD player, and for one or two video demos we used a Yamaha 901 laser disc player. A Denon 3800 surround-sound amplifier plus a NAD 317 amp were used.

But the spotlight for the night was on the speakers. Designed by Ralph Waters in Sydney, the Subsonic Fusion 3 System gave us all the audio for the night. This is a newly developed system comprising left and right main (i.e. front) speakers (model HT1) costing $3,500, a centre front speaker (model HT1C) at $1,500, and a pair of rear speakers (model HTMP) at $1000 the pair. (Hence the full speaker system costs $6,500). A feature of the system is that, although the cabinet shapes varied, all five main speakers were acoustically identical. They all used the same drivers in the same sized enclosures, with the same crossovers, etc. The exception was that the front three speakers had built in sub-woofers to complement the basic mid-range and treble units of the set. Whereas the mid-range and treble drivers were conventional passive speakers, active speaker technology is used for those speakers which have sub-woofers. Signals below 120Hz from all channels is monoed and sent to the three sub-woofers. Being active sub-woofers, they fit the bass drivers into relatively small enclosures, and use electronic circuitry to compene for the inevitable bass roll-off thus produced. Drivers used were SEAS and Audax. Each of the three speakers with subwoofers come complete with their own internal bass amp. This is a narrow bandwidth 220 watt amp giving very high levels of damping.

Software? Movies have been being recorded for theatre showing in 5-channel sound for years, and there are now plenty of movies available for home theatre use in 5-channel. Music, we are told, is about to be made available in 5-channel format, and there are the inevitable few around the place who claim to have seen or heard some.

The first few demonstrations were of music. Ralph played several CDs, ordinary stereo CDs, using just the left and right front speakers. Firstly a small pop group, guitar with bass guitar and drums. A twist of the bass volume control and he tried two or three different levels of bass. With this kind of musical material, who knows which one would be the most natural? Second sample was a track of electronic music, said to be chosen because it was demanding of speakers. But even more unhelpful if we wanted to evaluate how natural the speakers sounded. Certainly there was plenty of power, plenty of sound, plenty of "clarity".

Next a solo drumkit recording, something we could relate to live sound. Again the system showed an ability to produce high levels of clean sound. I thought the first run made the bass drum too "plummy", but a bit of bass boost on the sub-woofer and it all tightened up nicely. Then a track by a group called "Foreplay". Ralph pointed out that if speakers are any good, they should be able to reproduce all kinds of music - rock, punk, funk and junk, not to mention jazz, classical and anything else. One could only agree, while the thought came wryly that he had slipped up a bit on demonstrating such an ability.

And then, tarrah! The main game. All systems were turned on for the video demonstrations. Firstly there was a clip from The Fifth Element. Wow! The large projected picture surely was of cinema quality. Clean, crisp and bright. A questioner wanted to know why there was a need for a centre front channel, when you could clearly simulate sounds from a centre front position by the usual stereo technique of equal signals from left and right. Ralph's response was to replay a bit of a video sequence, once with centre channel turned off and once with it on. Of course, when centre channel was off, a lot of the sound wasn't there. But surely that was because the original recording had been made that way. The questioner's point was that a similar effect could have been produced without a centre channel or speaker if it had been recorded with the front like conventional stereo. (No doubt the real answer to the question is that the system was developed for cinemas in the first place, and all cinemas had a centre front speaker system already in place.) This all interested us in the light of Surya Moorthy's argument from the month before that a centre front channel is bound to cause trouble when you are trying to reproduce simple music with ambience.

We had some short film sequences with a flying boat coming straight for us, then lifting up and going just above us, and again with a large truck driving over the viewing spot. In each case, Ralph was trying to make the point that good cinema surround sound needs to be able to produce stereo-type imaging all around the plane, that is from left to right and from front to back simultaneously. To do this you need five identical speakers all around you, and the Subsonic Fusion 3 System does just that. I found his argument here totally convincing, and the demonstrations were spot on also. In each case, the sound tracked right across the room smoothly and evenly.

After a break for supper, we played some members' CDs in stereo, and this gave us a chance to hear the speakers on a wider range of music. From a Mercury CD, a snippet from An American in Paris, something from a B. B. King album Deuce is Wild and something else from Ben Sidron, Too Hot to Handle. Finally a flute solo and flute with harp plaing Clair de Lune. The flute was clear and sweet and natural sounding, but on most of the other music tracks I thought something sounded amiss. Sometimes harshness, other times boominess, and in several cases it sounded as though the frequency balance was not even through the range.

In summary, I thought the video demonstrations were thoroughly convincing. The picture quality was superb, the sound convincing, and the sound imaging was excellent right across the plane. Any home theatre set up that used this equipment could truly expect to produce results right up to theatre quality. For playing music, however, I thought that the system was not as good as a high quality dedicated stereo rig.

April 1998 The TAS Surround-Sound System

Surya Moorthy, of Absolute High End, 355 Burwood Road, Hawthorn, talks with missionary zeal about the "TAS" surround-sound system which he is helping to develop. Like Trevor Lees at a General Meeting a couple of months ago, Surya believes that the days of stereo reproduction of music are almost over, and that multi-channel audio of some kind is about to arrive.

According to Surya, the true purpose of surround-sound in the reproduction of music is not to enable us to hear music as though the players and/or singers are beside and behind as well as in front of us. It is to reproduce the acoustic ambience of the original venue that we need surround sound. Since we normally hear live music in some sort of a building, we are accustomed to hearing room ambience along with each and every sort of music that we know. "Natural" sound, he concludes, therefore means the central or main sound PLUS the accompanying ambience. A musical instrument heard out of doors and well away from reflecting surfaces "sounds unnatural". A trumpet played out of doors and close to a listener will be judged "harsh and bright" and not natural.

Mono sound reproduction was described as reproducing, all from the one location, the direct sounds emanating from all the musical performers. There is none of the secondary reflected sound that occurs in a real concert venue. Stereo reproduction gives a listener a good idea of numerous direct sound-sources spread across the sound-stage, but the ambience information is seriously impoverished.

Surya spent some time explaining that all large auditoria are to some extent reverberant, that is a sound emiited within such a space is sustained for a time by reflections from the surfaces within the room. The home listening room is not a reverberant space in the same sense for two clear reasons. One, most home lounge rooms contain much sound absorbing material in relation to their size – they are less reflective of sound. Two, their size is smaller that any musical performance venue, and what sound reflections there are arrive at a listener so soon after the direct sounds that there is no aural impression of a "room acoustic". We say that small rooms are incapable of sustaining a reverberant sound field.

As home listening rooms can't generate their own audible ambience, a truly satisfactory audio system in the home will need to produce room ambience comparable with that you would have heard in the original venue. This is what Surya's TAS system is trying to do. (TAS stands for "The Absolute Spatial").

How does it work? It works on ordinary standard stereo CDs. Some recordings give better results than others, presumably because we are relying here on extent to which the recording maker has happened to record secondary reflected sounf information. (We realise that a good recording engineer may not be actively seeking to exclude room reflected sounds from his recording, but his microphones are more or less directional, and if he is not going out of his way to encode ambience sounds, just what ambience he gets down might well be a matter of sheer chance. The TAS system reproduces the stereo signal unaltered from a pair of speakers at the front of the room. However, in the demonstration we heard, they were strange speakers indeed that Surya used, speakers that had been made specifically to his requirements by Colin Whatmough. The mains, stereo "direct sound" information came from a full complement of speaker drivers which pointed towards each other at the front of the room. That is, the traditional stereo signal was transmitted along lines at right angle to the line to the listener. An special TAS processor unit is used to select out-of-phase components in the original recording, amplify these and reproduce them from forward facing drivers in the front pair of speakers as well as from a pair of speakers in the two rear corners of the room. Surya indicated that on some recordings, switching TAS into the system makes little difference to the overall sound. These are recordings which happen to contain little ambience information. Others, especially recordings made using simple microphone techniques show a vast effect when played via TAS.

Surya played us a number of CDs spaced throughout his discussion, all standard stereo CDs. We had a large audience of over 50 people crowded tightly into a room which was very hard pressed to cope with such a number. Yet people all over the room were reporting that they were able to locate the positions in space of the performers. This contrasts with a standard stereo reproduction, where people well off the centre line have great difficulties in spacially locating the performers.

This was pretty confronting stuff. Here was an audience of audiophiles, all accustomed to some degree to seeking to perfect the reproduction of music from a system which Surya was arguing could never work.

What did I think?

I think that Surya overstates the situation in saying that music without concert hall ambience sounds "unnatural". There is nothing at all unusual in hearing live music out of doors. I recall some superb recitals that the Southern Command Army Band used to give at lunch times in the open at the front of the Rialto building every month when I worked in there. We hear music in the open at marches, parades, sporting events. Likewise, many of us hear plenty of music in rooms too small to sustain a reverberant sound field. Ask Doug T, or John D, or Bruce B, or plenty of others. My wife plays piano, cello, flute and guitar in our home, and all three kids learn musical instruments. I hear live music every day in the same room in which I listen to stereo reproduction. I don't think that live music heard without a large-hall ambience sounds in any way "unnatural". To me it sounds like natural music in the open air or live music in a small room. It's different from live music in the Concert Hall, but not less natural.

For all that, I am prepared to concede Surya's point to the extent that music reproduced with proper room ambience is likely to sound more attractive than without. If that is so, then the search for a system which will reproduce music like the present good stereo and with a realistic impression of room ambience should be worthwhile.

Is TAS the answer? Well I have to say that I have some doubts. Notes I made during Surya's demonstrations include things like - "…. in TAS mode a more reverberant, mushier sound", and "TAS mode gave less strident frontal sound, but a little dull" and "in TAS it sounded better than the stereo on that system, but muffled, not "attacking" enough". So in summary, I thought that this system in TAS lacked sparkle and immediacy. Could we really be surprised? The main "direct sound" drivers, including tweeters, were firing in a line at right angles to where I was sitting. How could the system be anything other than lacking in sparkle?

I wonder If the TAS background philosophy is quite right. At one stage Surya said that "It has long been the objective of concert hall acoustic engineers to design halls of high spatial impression. The higher the spatial impression the greater will be the listener'' feelings of being surrounded and enveloped by the sound"" Well, that would not be my ideal for a concert hall. Sounds more like St Paul's or St Pat's cathedral. Large and very reverberant spaces can handle choral or organ music if it is slow moving and deliberate. But try to perform music with rapid figurations in it and all the detail gets lost in the reverberation.

I think that a good venue for music lets us hear the direct sound from the performers cleanly, crisply and in proper balance, and adds a light patina of reflected reverberation to give a touch of warmth. I suspect that Surya's system might be giving us too little of the main game and too much of the warmth.